LakeTahoeQuattro

Yes there was some dark crap in the bottom of the expansion tank. I figured it for dirt. When I initially got the car it had pink coolant in it. When I pulled the engine I did a quick swap and did not do a flush. When I replace the radiator I will flush the cores and drain the block. What chemical agent do you suggest I use?

Also about the aux heater? Do you think it is shot if I can not feel the solenoids pulsing?

LakeTahoeQuattro

Ok radiator and aux pump are in the mail. Will report back after chemical flush of heater cores and installation of parts. Fingers crossed.

LakeTahoeQuattro

I am most certainly frustrated to say the least. Replaced aux pump and radiator to have the exact same symptoms. Was very careful this time to bleed coolant properly. I am certain there is no air in the heater cores.

I can not feel the solenoids pulsing either. "Rest" button does activate the pump still.

I did notice something interesting. The rear vent blows hot hair. Is that on an electric heater? I remember reading somewhere that the touaregs and the d3's had an electric heater back there.

silverd2

Frustrating indeed.

The rear vents in a D2 are just extensions of the front vents ... no electric help.

Forgive me if you have answered this, but did the old thermostat produce the same temps?
Was the water pump replaced? ...worst case scenario: water pump slipping internal or rotted away impeller(?) ... not a common problem, though.

Cheers

LakeTahoeQuattro

Yes old thermostat was a Mahle Behr. Replaced it with OEM and same symptoms. New water pump as well. At this point I am stumped.

silverd2

Does the temp vary any with speed?

Not a cure, but a monitoring tool built into the car: Climate control "secret codes" ... code 102 to watch fluctuating temp while driving....since the car has an "idiot gauge that reads "perfect" from 81-100C before it moves off the "perfect" hash mark.

quattroworld.com Forums: Climate control secret codes (Facelift D2 A8/S8) >>>>>

LakeTahoeQuattro

Yea I have been driving around on channel 102 all the time now haha. Most of the time on the freeway it is 100. Under full throttle up a hill or something it goes up to 107

silverd2

That kinda rules out a fan problem (in my opinion)...with no fan at all and a clean radiator, the temp would still drop way below 100C (probably down to 90C) on the freeway.

Too many people knee-jerk into a fan analysis, when that rarely leads to general hot running ... esp at speed.

Running out of theories...but has to be something, though. With all working as intended, these cars don't tend to run hot at all.

silverd2

PS: Have you basically checked the physical resistance of the viscous clutch fan?

LakeTahoeQuattro

Yea in my allroad with efk, it rarely turns on unless it is very hot outside or I am beating on the car. It maintains temperature just fine. I would say my efk turns on 60% of the time while at idle in the summer. 1% of the time while at idle in the winter. Never while moving down the road.

No I have not stuck a carrot in the fan yet. Just by touch the fan clutch seems to have the resistance of a new clutch. It will not spin by hand.

I have been ignoring this sound thinking it was a faulty serp belt tensioner or fan bearing. I have not yet diagnosed it by removing the serp belt. Is this a sound of a bad water pump maybe? Just took this vid of my car.


I found this guy here who said he replaced his water pump, just to need to replace it again because it was bad. Engine over heating - Audi A8/S8 - TyreSmoke